This invention relates to joints in air passages through which flows matter capable of abrading the joints, and more particularly to a vacuum cleaner power nozzle having an articulated joint in the air passage between the power nozzle body and the hose coupling thereof.
In canister-type vacuum cleaners, the suction motor unit and the dust-collecting bag are housed in a body which rests movably on the floor. A flexible hose is connected at one end to an orifice in the body, and any of various cleaning attachments can be connected to the other end of the hose. A rigid section, commonly referred to as a "wand," can be interposed between the end of the flexible hose and the attachment. As used herein, the term "hose" includes both the flexible and the rigid portions of the hose.
One type of cleaning attachment which is provided for use with canister-type vacuum cleaners is the power nozzle. This nozzle, which is designed primarily for use on rugs and carpets, has a separate motor within its body which drives a rotary device, such as a brush or beater, for agitating the carpet surface to loosen dirt and for separating matted-down fibers. The brush is disposed in the air passage through which the flow of suction air removes the loosened dirt.
This air flow passage terminates in a coupling to which the hose is connected. In order for the user to be able to maneuver the nozzle easily, an articulated joint is usually provided in the air flow passage at a point between the body and the coupling, so that the angle between the hose and the floor at the coupling is freely variable.
An early joint of that type included a fork hinged to the rear of the body. The coupling depended from the fork. A flexible hose connected the air flow passage in the body to the coupling, passing between the legs of the fork. The fork and the coupling could thus be pivoted in a vertical plane without disrupting the air flow passage.
A more recent joint of that type includes a chamber having walls defined by the body of the nozzle, and a tubular member having a portion disposed within the chamber. A second portion of the tubular member extends from an opening of the chamber and terminates in the coupling. The portion of the tubular member disposed within the chamber is movable about a horizontal axis extending from one side of the chamber to the other, so that the tubular member can be pivoted in a vertical plane. An opening in the portion of the tubular member within the chamber is configured so that the air passage remains open regardless of the pivot angle, yet the opening is never exposed outside the chamber.
In that joint, dust and dirt in the air flow can enter between the outer walls of the tubular member and the inner walls of the chamber. In addition, portions of the outer walls of the tubular member are exposed to the flow of dust-laden air within the chamber. Additional dust enters the area between the outer walls of the tubular member and the inner walls of the chamber after it is deposited on the outer walls of the tubular member which is then pivoted so that these walls come in contact with the inner walls of the chamber. If such a joint were made of metal, this accumulation of dust may not pose any problems, as metal is harder than dust. However, such joints are now commonly made of plastic Frequently, dust and dirt particles are harder than the plastic of the joint. As a result, dust trapped between the outer walls of the tubular member and the inner walls of the chamber acts as an abrasive, damaging the plastic joint as it is repeatedly pivoted.
The need exists for a means to prevent abrasion damage caused by dust in a plastic articulated joint, in the air flow passage of a vacuum cleaner power nozzle, of the type having a tubular member disposed within a chamber defined by the nozzle body.